Piano key-bottom



(No Model.) `r W. H. .IVERS.

PIANO KBY BOTTOM. I No. '382,4'71. Patented May 8, 1888.

EIIIIIIIIIIL-` UNIT D STATES PATENT OFFICE.,

WILLIAM H. IVERS, OF DEDHAM, ASSIGNOR TO THE IVERS 83 POND PIANO COMPANY, OF BOSTON, MASSACHUSETTS.

PIANO KEY-BOTTOM.

SPCIFICATION forming part of Letters Patent No. 382.471, dated May 8, 1888.

(No model.)

TO all whom it ma concern:

Be it known that LWILLIAM H. IVERS, a citizen of the United States, residing at Dedham, in the county of Norfolk and State of Massachusetts, have nvcnted certain new and useful Improvements in Piano-Fortes; and I do hereby declare the following to be a full, clear, and exact description of the iuvention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to upright pianos, and is embodied in the mechanical features by which the key-bottom, so called, is st ffened and supported centrally between the ends of the instrument.

The drawings represent, in Figure 1, a front view; Fig. 2, a vertical transverse section of a piano embodying my improvements. Fig. 3 is an enlarged view showing the adjustable mechanism by which the key-bottom is secured to the support.

Musical instruments of the class above mentioned are generally composed of two portions containing the various instrnnentalities which, combined, form the piano as an entirety. For convenience of description these two portions may be divided by a vertical plane, :c w, the portion marked A of which, to the rear of said plane, contains the frane, skeleton plate, strings, and sounding-board. The part in front (designated B) contains the keybottom, keys, and action, so termed.

The instrument is formed at the ends with two vertical pieces, O O, which form a portion of the case, and between which is horizontally disposed the key-bottom D. The latter consists of a solid rectangular piece of wood; or it may be made up of a series of strips firmly glued together. As an entirety it is permanently secured to the ends C C of the case at a point about midway between the top and bottom of the instrument. When said keybotton was loaded with the keys and action, it became very liable to yield or spring centrally, consequent upon jars or shocks resulting fron transportation or removal of the instrument,

while, furthernore, changes in its position frequently occurred, due to Varying atmospheric influences.

Since the entire weight of the keys and action is sustained by the key-bottom, their proper position and adjustment relatively to the strings are likewise dependent upon the rigidity and permanency of said key-bottom, and it is evident to those skilled in the art that the result of any disturbance in the position of the key-bottom affects the adjustnent throughout the entire series ofkeys,the action, and the strings which co operate therewith; hcnce the object of my invention is to support'the key-bottom not only at its extremities a a where the latter are joined to the end pieces, G G, but also centrally, where no support hitherto has been given. This I eifect by means of the netallic brace or strut E, which is centrally bolted to the key-bottom at I b. The opposite ends of said brace are bolted or otherwise fastened to the end pieces, C C, of the piano-case. This brace or truss may be varied in shape longitudinally, as well as in cross-section,to conform to circumstances. To more pernanently secure and retain the key-bottom in a certain fixed position, or to enable adjustment thereof, if required, to be readily effected, I have inserted a bolt', c, pernanently in the key-bottom. When thus positioned, said bolt extends downwardly, passes freely through a hole, d, bored in the brace E, and projects beyond. This protruding part is screw-threaded and furnished with a nut, e. When the brace or supportE has been firmly secured to the end pieces, O C, the key-bottom can be adj usted centrally in horizontal planes by the movement of the nut on the bolt; hence it is evident that any tendency to rise or fall, in fact any movement which may cause it to deviate from its normal horizontal position, can be controlled by the brace in conjunction with the adjusting bolt or bolts. By this arrangement a wooden key-bottom can be rendered as stiff and permanent as one made entirely of met-al, and is very much lighter. Moreover, the brace, which extends downwardly upon the ends C G of the case, serves to render the latter part of the instrument more rigid, while at the same time affording a permanent sup port to the key-bottom eentrally, as hereinhefore premised.

One proninent advantage in this method of supporting the keybottom by means of the bruce E, it will be observed,eonsists in seeuring the two extrenities of said bruce to the end pieces in which the fiber eomposing theni is set vertieally. Therefore the brace is upheld by end wood, which afords the greatest resistance to a load, and there is consequently little orno tendeney to spring, ield, contract, or expand.

What I claim und desire to secure is- 1. In piano-forms provided with a key-botton and the end pieees to which said key-bottom is Secured, a netzliie braee, suhstuntially 

